Ch. 19 Flashcards
Structural Proteins
Provide structural components
Ex: Collagen is in hair and tendons. Keratin in hair and skin
Contractile Proteins
Make muscles move
Ex: Myosin and actin contract muscle fibers
Transport proteins
Carry essential substances throughout body
Ex: Hemoglobins and lipoproteins
Storage proteins
Stores nutrients
Ex: Casein
Hormone proteins
Regulate body metabolism and nervous system
Ex: Insulin and Growth Hormone
Enzyme proteins
Catalyze biochemical reaction in cells
Ex: Sucrase and Trypsin
Antibody (proteins)
Recognize and destroy foreign substances
Ex: Imminoglobins
How are amino acids classified?
Nonpolar (hydrophobic)
Polar amino acids
Polar neutral
Polar acidic
Polar basic
Which amino acids are nonpolar?
Glycine (Gly, G)
Alamine (Ala, A)
Valine (Val, V)
Leucine (Leu, L)
Isoleucine (Ile, I)
Phenylalanine (Phe, F)
Methioinine (Met, M)
Proline (Pro, P)
Tryptophan (Trp, W)
Polar amino acids
Serine (Ser, S)
Threonine (Thr, T)
Tyrosine (Tyr, Y)
Cysteine (Cys, C)
Asparagine (Asn, N)
Glutamine (Gln, Q)
Polar acidic amino acids
Aspartate (Asp, D)
Glutamate (Glu, E)
Polar basic amino acids
Histidine (His, H)
Lysine (Lys, K)
Arginine (Arg, R)
Which amino acid is the only achiral one?
Glycine
Amino acids are nonpolar when?
When the R group is H, Alkyl, or Aromatic
Amino acids are polar when?
R group is an alcohol, thiol, or amide
Amino acids are polar acidic when?
They have carboxyllic acid group
What’s a peptide bond?
An amide bond that forms when the COO- group of one amino acid reacts with NH3+ group of the next amino acid
What is a peptide?
Linking of 2 or more amino acids by peptide bond
What is the primary structure of a protein?
The particular sequence of amino acids held together by peptide bonds
11 essential amino acids
Histidine (His, H)
Isoleucine (Ille, I)
Leucine (Leu, L)
Lysine (Lys, K)
Methionine (Met, M)
Phenylalanine (Phe, F)
Threonine (Thr, T)
Trytophan (Trp, W)
Valine (Val, V)
What is a secondary structure?
Structure that forms when amino acids form hydrogen bonds between the atoms in the backbone on the same or another peptide chain
Types are alpha and beta
Secondary Structure: Alpha Helix
Hydrogen bonds form between the oxygen of the C=O groups and the hydrogen of N-H groups of the amide bonds in the next turn of alpha helix
What gives the helical shape in the alpha helix?
Formation of many hydrogen bonds along polypeptide chain
Secondary Structure: Beta pleated sheet
Hydrogen Bond forms between the carbonyl oxygen atoms and hydrogen atoms in the amide groups bending the polypeptide chain into a sheet
What are the R group interactions that contribute to making a tertiary structure?
Hydrophobic interactions
Hydrophilic Interactions
Salt Bridges
Hydrogen Bonds
Disulfide Bonds
Hydrophobic Interactions
Occur betwen 2 amino acids that have nonpolar R groups
Hydrophilic Interactions
Occur between external aqueous environment and the R groups of polar amino acids
Salt Bridges
Ionic Interactions between ionized R groups of polar basic and polar acidic amino acids
Hydrogen Bonds
Form between the H of a polar R group and the O or N of another polar amino acid
Disulfide bond
Covalent Bonds that form between the SH groups of cysteine residues in a polypeptide chain
